What Are The Malfunctions Of Bosch Rotary Hammers And How To Fix Them Yourself

2023 Author: Philip Bishop | [email protected]. Last modified: 2023-08-25 07:54

• Mechanical malfunction of the Bosch rotary hammer
• The hammer drill stops hammering, but drills
• The hammer drill stopped drilling, but hollows
• Consider the options in which the hammer drill does not hammer, but drills
• Consider the options in which the hammer drill drills, but does not hammer
• Consider the options in which the hammer drill does not drill or hammer
• General electrical malfunctions of the Bosch rotary hammer 2-26

Nothing is eternal. And the most reliable Bosch rock drills start to break over time. But any malfunction can be repaired by hand if you have a detailed guide on how to carry out repair work. Below we offer you a guide to troubleshooting Bosch rotary hammer drills and how to fix them.

The main reasons for the appearance of breakdowns are:

• sloppy work with the tool;
• improper storage of the punch;
• heavy loads when working on working bodies when chiselling or drilling;
• overheating of the tool;
• long-term work without interruption;
• failure to comply with the terms of maintenance.

Conditionally, faults can be divided into mechanical and electrical.

Next, we will consider the faults by their belonging, dividing them into mechanical and electrical faults.

Mechanical malfunction of the Bosch rotary hammer

When mechanical malfunctions appear in the operation of the instrument, an extraneous unpleasant sound appears, sparking increases in the collector area, a burning smell appears, the instrument heats up excessively, its power decreases depending on the duration of work and the effect on the material.

We will consider all the malfunctions on the Bosch 2-26 perforator diagram. The rest of the models, such as Bosch 2-20, 2-24, differ in the design of the intermediate shaft, the installation of various drunk bearings.

The hammer drill stops hammering, but drills

The hammer drill does not hammer under load or idle for the following reasons:

• the rubber rings of the striker, striker, piston are worn out;
• the rolling bearing cage collapsed;
• the cylinder collapsed, the firing pin of the barrel of the percussion mechanism;
• cut the splines of the clutch mounted on the intermediate shaft;

The hammer drill stopped drilling, but hollows

The main reasons for the hammer to hammer but not drill are:

• the force of the conical spring, pressing the clutch, has weakened;
• the locking roller does not fix the large gear of the barrel shaft;
• does not hold the tool locking mechanism in the barrel;
• The hammer drill does not hammer or drill.

The main reasons why the hammer drill does not hammer or drill are:

• sheared teeth on the small rotor gear or on the large countershaft gear;
• the hammer drill motor does not work;
• there is no power to the hammer drill motor.

Now about everything in order

Consider the options in which the hammer drill does not hammer, but drills

Wear of rubber rings on the striker, striker, piston.

This reason appears gradually, as the rubber rings wear. At first, the blow weakens, then disappears altogether.

The malfunction is eliminated by replacing the indicated rubber rings with new ones.

For any repair of perforators, its assemblies, all rubber products are subject to replacement.

Collapsed rolling bearing race (drunk bearing)

When the drunk bearing, pos. 830, is destroyed, the rotary movement of the intermediate shaft cannot be converted into the translational movement of the cylinder in the percussion mechanism.

Eliminated by completely replacing the rolling bearing.

The cylinder, striker, barrel striker of the shock mechanism collapsed

There are times when the drummer bites into the cylinder, pos. 26, which leads to the destruction of the cylinder and the impossibility of creating air pressure in the barrel of the impact mechanism. And the second reason: the destruction or breakage of the striker pos. 28, leading to the distortion of the part and the impossibility of transmitting the shock impulse.

Breakdowns are eliminated by completely replacing the failed parts.

Cut off the splines of the clutch poz.67 installed on the intermediate shaft

The malfunction is eliminated by repairing the clutch or completely replacing it.

When repairing the clutch, worn teeth are cut down. To correct this defect, a round file and a drill are used. The clutch is clamped in the hand, and the tooth profiles are straightened with a drill with an appropriate file. The splines on the intermediate shaft are similarly modified.

Consider the options in which the hammer drill drills, but does not hammer

The force of the conical spring pressing the clutch has weakened

When the spring pressure (pos. 50) decreases, the clutch slips on the intermediate shaft, without transferring rotation from the small spur gear to the large gear (pos. 22) of the barrel shaft, pos. 821, of the impact mechanism. By the way, the clutches are arranged differently on different Bosch models.

The lock roller does not lock the large barrel shaft gear

Big gear, pos. 22, is attached to the shaft of the barrel, pos. 01, by a roller, pos. 88, pressed against the shoulder of the shaft by a conical spring, pos. 80, and fixed with a retaining ring, pos. 85.

The reason may be a weakening of the force of the conical spring, pos. 80, destruction of the retaining ring, pos. 85, falling out of the fixing roller, pos. 88.

Does not hold the drill mechanism for fixing the tool in the drill barrel

Bosch rotary hammers use two types of chucks: SDS-plus and SDS-max. The difference is in the design of the locking mechanism.

The reason is the wear of the antennae of the raster sleeve of the chuck, which leads to the impossibility of transmitting the shock pulse to the working tool of the perforator.

Consider the options in which the hammer drill does not drill or hammer

Cut teeth on the small rotor gear

There is a rotation of gears with cutting teeth on one of them, more often on a small one.

When the working tool is jammed and the clutch does not work properly, there is wear or complete destruction of the gear teeth on the perforator shaft and the intermediate shaft.

In this case, the rotor or the large gear of the intermediate shaft changes completely.

The hammer drill motor does not work

The reasons for a not working electric motor can be:

• short circuit in the rotor, stator;
• destruction of coal electric brushes;
• loosening the fastening of the brush holders;
• burnout of lamellas on the rotor manifold;
• breakage of the rotor or stator windings.

The listed malfunctions are eliminated by repair (manually rewinding the winding, replacing the collector and wiring the winding leads) or replacing the rotor, stator, carbon electric brushes with new ones.

The main part of the malfunctions of the electrical part of the Bosch 2-26 rotary hammer is confirmed by increasing sparking in the collector area.

The length of serviceable electric brushes cannot be less than 8 mm. When replacing one brush, the second should change automatically.

The rotor or stator windings can be rewound independently with your hands at home.

No power to the electric motor of the Bosch rotary hammer

The reason for this malfunction is a break in the wire that supplies power to the electric motor. Most often, a break occurs at the point where the cable enters the puncher. The wire should be replaced with a new one or repaired. The malfunction can be determined with a tester. If there is no tester, the fault can be found using the power phase and a screwdriver with an indicator neon lamp. Connecting the power wires in turn, at the other end, using a neon screwdriver, determine the presence or absence of a phase.

The punch button does not work. Determined by the short circuit tester.

Most often, a short circuit of the filter capacitor leads to the failure of the punch button. It is best to replace the button with a new one.

General electrical malfunctions of the Bosch rotary hammer 2-26

Failure of the punch in the electrical part is accompanied by the appearance of a burning smell, strong heating of the tool during operation, the appearance of large sparking in the area of the punch rotor collector, poor operation of the reverse switch.

The operation of the perforator is influenced by the condition of the carbon brushes, the reliability of the attachment of the brush holders and their correct installation.

A burning smell appears when the stator or rotor windings are short-circuited.

A drop in the power of the perforator with increasing load is characteristic when there is a break in the rotor windings or with a short length of carbon brushes.

A short interturn circuit in the stator or rotor most often leads to heating of the perforator.

Large sparking in the collector area is caused by inter-turn closure of the rotor or burnout of the collector lamellas.

Disruption of the reverse switch is due to the burning of its contacts.

But the main reason for all breakdowns is the untimely performance of technical maintenance work and the replacement of carbon brushes.

Carbon brushes need to be replaced after 70 hours of operation or when worn up to 8 mm in length.

We have given the main reasons for the failure of Bosch rotary hammers.

Perhaps we have not described all the breakdowns of Bosch rotary hammers.

If you know other malfunctions with Bosch rotary hammers 2-20, 2-24, 2-26, share with us.

I wish you success!

Video of replacing the raster sleeve in the Bosch chuck 2-26

Video of replacing the anchor in the Bosch rotary hammer 2-26